python語言常見問題

python語言常見問題

1. 編譯錯誤

1.1. TabError: inconsistent use of tabs and spaces in indentation

C:\timer>python getAllTitles.py
  File "getAllTitles.py", line 192
    startTime = datetime.datetime.now()
                                      ^
TabError: inconsistent use of tabs and spaces in indentation

• 在Sublime Text編輯器中檢查代碼發現：
  

這個錯誤的原因是，在代碼中用了tab鍵做縮進了，python和其他語言（c,c++,java）不同，它是用縮進來區分程序塊。
解決方案就是：把Tab鍵換成4個空格。如下圖所示：

2. 語法問題

2.1. try…finally 和 return之間的關係

• 參考文章：Python：淺析 return 和 finally 共同挖的坑 http://python.jobbole.com/88408/

def func():
    count = 0
    mark = 0
    try:
        mark = 1
        count += 5
        print(f"1. count = {count}, mark = {mark}")
    except Exception as e:
        mark = 2
        count += 5
        print(f"2. exception: count = {count}, mark = {mark}")
    else:
        mark = 3
        count += 9
        print(f"3. count = {count}, mark = {mark}")
        # 這個時候，其實已經把count=14, mark=3這兩個值送入到return函數中
        # 然後再執行finally語句
        # 最後，再從return函數中出來
        return (count, mark)
    finally:
        mark = 4
        count += 11
        print(f"4. count = {count}, mark = {mark}")

if __name__ == "__main__":
    result = func()
    print(f"result = {result}")

# 打印結果
1. count = 5, mark = 1
3. count = 14, mark = 3
4. count = 25, mark = 4
result = (14, 3)